Threads - Server Side

The code bellow is a server code that will continuesly wait for a
vector object from the client side. There are many clients that will
be connected to the server. Must I use threads to handle the many
clients?. Is it advisable to implement threads and why?

import java.net.*;
import java.util.*;
import java.io.*;
public class GandhiServer2
{
    ServerSocket ss;
    Socket cs;
    Vector ht;
    ObjectInputStream ois;
    public GandhiServer2()
    {
        try
        {
            ss = new ServerSocket(9000);
            cs = ss.accept();

            while(cs.isConnected() == true)
            {
             ois = new ObjectInputStream(cs.getInputStream());
             ht = (Vector)ois.readObject();
             System.out.println(ht);
             cs = ss.accept();
            }

        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

    }

    public static void main(String[] args)
    {
        new GandhiServer2();
    }
}

Regards.